Mold apparatus for making foamed-in-place double-skin building panel

ABSTRACT

Mold apparatus for making a double-skin construction panel of the type having spaced-apart inner and outer facing sheets and a foamed-in-place core filling the space between the facing sheets. The mold apparatus includes upper and lower mold platens which when assembled, present confronting, laterally offset, upper and lower U-shaped cavities. The cavities are adapted to receive the complementary facing sheets and to position them in fixed, juxtaposed, laterally offset relation.

United States Patent 1 Howell et al.

in] 3,759,,e79

[451 Sept. 18,1973

[ MOLD APPARATUS FOR MAKING FOAMEDJN-PLACE DOUBLE-SKIN BUILDING PANEL[75] Inventors: Norbert C. Howell, Connersville;

Walter Tlschuk, Richmond; Thomas M. Welsh, Connersville, all of Ind.

{73] Assignee: H. II. Robertson Company,

Pittsburgh, Pa.

[22] Filed: Mar. 24, 1971 21 Appl. No.: 127,615

Related US. Application Data [60] Continuation-impart of Ser. No.71,493, Sept. 11, 1970, abandoned, which'is a division of Ser. No.732,689, May 28, 1968.

[52] US. Cl 249/95, 425/109, 425/123,

425/817 [51] Int. Cl B22d 19/04 [58] Field of Search 425/109, 123, 817;

[56] References Cited UNITED STATES PATENTS 3,135,640 6/1964 Kepka425/817 326,878 9/1885 Lernassena 425/408 X 3,248,758 /1966 Schmitz etal. 425/408 3,431,331 3/1969 Pincus et a1. 425/408 X 3,396,430 8/1968Westcott 425/109 Primary Examiner- H. A. Kilby, Jr. Attorney-Harry B.Keck and George E. Manias s7 ABSTRACT Claims, 12 Drawing Figures 4 M M E59 J L/\\\\\ p 5/1 J 59 g L g 15 75 PATENTEDSEPIQIQH 3.759'479 SHEET 2BF 4 98 r W W 56 4! WALTER TISCHUK THOMAS M. WELSH AGENT PAIENTEUSEPIBMH3'759'479 SHEET 3 BF 4 A234 93 W /20 (/29 12/ 77 82 //4, #5, M ms;

J k. 76 60 //5 04 45: L/ZZB /29 w 75 INVENTORS NORBERT C. HOWELL WALTERTISCHUK THOMAS M. WELSH MOLD APPARATUS FOR MAKING FOAMED-IN-PLACEDOUBLE-SKIN BUILDING PANEL CROSS-REFERENCES TO RELATED APPLICATION (IFANY) BACKGROUND OF THE INVENTION l. Field of the Invention Thisinvention relates to mold apparatus for making double-skin buildingconstruction panels having a foamed-in-place core.

2. Description of the Prior Art Heretofore, double-skin building panelswith a foamed-in-place plastics core have been fabricated in elaboratemolding apparatus requiring complex molds and extensivepressure-retaining components for confining the appreciable pressureswhich are created by the expanding organic foam materials. See forexample U. S. Pat. Nos. 2,866,730; 3,090,078; 3,203,042. In otherinstances the excessive pressure buildup of the rising organicfoamed-in-place plastic core is avoided by deliberately providinginsufficient foam to fill the open space of the panel, see for exampleBelgium Pat. No. 696,876.

SUMMARY OF THE INVENTION suited for the manufacture of buildingconstruction panels of the type having complementary inner and outerfacing sheets and a plastic foam core which is formed by foamed-in-placetechniques preferably from polyurethane. Each of the facing sheetsincludes a central web having side walls formed along the oppositelongitudinal edges thereof and extending generally perpendiculartherefrom. When assembled, the side walls of the outer facing sheet arelaterally offset from the side walls of the inner facing sheet, thatisthe adjacent side walls are laterally spaced-apart, with a gaptherebetween. The foamed-in-place plastic core is visible at each of thegaps.

In accordance with the present invention, relatively simple mold platensare provided, each including a mold plate having opposite ends and firstand second opposite side portions. A side rail is secured to the moldplate along the first side portion and presents an upper surface remotefrom the mold plate. A spacer element is carried at one of the sideportionsof the'mold plate. The mold platens are adapted to be assembledin confronting relation with the side rail of each mold platenconfronting the second side portion of the confronting mold plate andwith each spacer element positioned between the side rail of one moldplaten and the opposing mold plate. When assembled, the mold platenspresent confronting, laterally offset, upper and lower generallyU-shaped cavities, each defined by the mold plate, the spacer elementand the side rail of each mold platen. Each of the cavities is adaptedto receive one of the complementary facing sheets.

In accordance with one embodiment of the present invention, the overalllength of the upper and lower mold platens may be equal to or greaterthan the overall length of the complementary facing sheets. The siderail of each mold platen is secured along one side portion of the moldplate while the spacer element is secured along the opposite sideportion of the mold plate. When assembled, the spacer element of eachmold plate engages a surface of the side rail of the opposing moldplate.

In accordance with an alternative embodiment of the present invention,the overall length of the upper and lower mold platens may be equal toor greater than the overall length of the complementary facing sheets.The side rail is secured to one of the side portions of the mold plate.In this embodiment, the spacer element is formed integrally with theside rail and is positioned to engage a face portion of the confrontingmold plate.

In accordance with the further alternative embodiment of the presentinvention, upper and lower mold platens are provided each having anoverall length which is substantially less than the overall length ofthe complementary facing sheets. The complementary facing sheets arepositioned in fixed, juxtaposed, laterally offset relation by l a set oflower mold platens assembled in longitudinally aligned end-to-endrelation and (2) a set of upper mold platens assembled in longitudinallyaligned end-to-end relation. Each of the mold platens (upper or lower)is provided with a female side rail along one side portion of the moldplate and a male spacer element along the opposite side portion thereof.The portion of the mold plate extending between the female side rail andthe male spacer element has a rhomboidal configuration in plan,including parallel opposite side portions and parallel opposite endsextending diagonally between the parallel side portions. The female siderail and the male spacer element include ends projecting beyond thecorresponding ends of the mold plate. When adjacent mold platens areassembled, a gap is provided between the adjacent mold plates. The gapprecludes the formation of mold marks in the facing sheet contained bythe adjacent mold platens.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective endview of two complementary mold platens, each carrying a facingv FIG. 5is a cross-sectional view, similar to FIG. 2, il-

, lustrating twoof the mold platens of FIG. 4 arranged in assembledrelation;

FIG. 7, illustrating the position of the mold platens dur-' ing theintroduction of a quantity of actively foaming plastics composition.

FIG. 9 is a plan view illustrating the exterior face of a mold platen ofFIG. 6;

FIG. 10 is a plan view illustrating the interior face of g a mold platenof FIG. 6;

FIG. 11 is a plan view illustrating a plurality of the mold platens ofFIG. 6 assembled in end-to-end abutted relation; and

FIG. 12 is a fragmentary plan view, similar to FIG. 11, illustrating analternative arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) The mold apparatus of thisinvention is employed to produce a foamed-in-place double-skin buildingconstruction panel of the type described and illustrated in copendingapplication Ser. No. 86,425, filed Nov. 3,

FIGS. 1 and 2 illustrate mold apparatus M comprising two relativelysimple and identical upper and lower mold platens 80, 81. Each of themold platens 80, 81 comprises a mold plate 82 provided with a side railor spacer element 83 and a side rail 84 along its opposite longitudinalside portions 75, 76. The side rails 83, 84 present opposed second andfirst longitudinal faces 85, 86, respectively,which are laterally offsetfrom one another and between which the facing sheets 35, 36 are pressfitted and retained. The side rail 83 presents a plain face 87. The siderail 84 presents a contoured face 88 including a lengthwise depression89, a length wise projection 90 and a plain surface portion 91. The

spacer element 83 has a width which is less than that of the side rail84.

When assembled, the upper and lower mold platens 80, 81 presentconfronting, laterally offset, upper and lower generally U-shapedcavities 121, 122, each defined by the mold plate 82, the secondlongitudinal face 85 of the spacer element 83 and the first longitudinalface 86 of the side rail 84. As shown in FIG. 2, the cavities 121, 122receive the facing sheets 35, 36, respectively. Thus the mold apparatusM positions the complementary facing sheets 35, 36 in fixed juxtaposed,laterally offset relation.

The lengthwise depression 89 of the upper mold platen 80 is adapted toreceive the lengthwise rib 49 provided in the second flange46 of thefacing sheet 35. The lengthwise depression 89 of the lower mold platen81 is adapted to receive the lengthwise rib 49 provided in the secondflange 46 of the facing sheet 36. The lengthwise projection 90 of theupper mold platen is adapted to receive a lengthwise trough 48 of thefirst flange 45 of the facing sheet 36. The lengthwise projection of thelower platen 81 is adapted to receive the lengthwise trough 48 of thefirst flange 45 of the facing sheet 35. The plain surface portions 91 ofthe side rails 84 of the upper and lower mold platens 80, 81 arepositioned to engage the corresponding plain faces 87 of the side rails83 of the lower and upper mold platens 81, 80. Preferably, the width ofthe upper mold platen 80 is substantially equal to the width of thelower mold platen 81.

When manufacturing the building panel 34, it is desireable to cap theopposite ends of the facing sheets 35, 36 to assure complete filling ofthe panels with the foamed-in-place' core. As shown in FIGS. 1 and 3,the opposite ends of the facing sheets 35, 36 are provided withpreformed end closures 79. When the facing sheets 35, 36 are broughttogether in opposed relation (FIG. 2), the preformed end closures 79effectively seal the panel ends and assure that the foamed-in-place core'55 completely fills the void space between the engaged enclosures 79and the facing sheets 35, 36.

During fabrication of the building panel, a quantity of actively foamingplastic composition 92 is distributed along the length of one of thefacing sheets, in this instance the inner facing sheet 36. While theplastic composition is foaming, the upper mold platen 80 containing thecomplementary facing sheet 35, is engaged with the lower mold platen 81,as shown in FIG. 2. It should be readily apparent by inspection of FIG.2, that the contoured surfaces 88 of the side rails 84 serve to alignthe complementary facing sheets 35, 36 is fixed juxtaposed, offsetrelation when the upper and lower mold platens 80, 81 are brought intoassembled relation. The opposite first and second side walls 43, 44 ofeach of the facing sheets 35, 36 confine the expanding plasticcomposition 92 in a direction parallel to the central webs 40.Accordingly, only unidirectional restraining pressures, applied in thedirection of the arrows 93 to the upper and lower mold platens 80, 81,are required by the present mold apparatus M. It will also beappreciated that the unidirectional restraining pressures appliedagainst the upperand lower mold platens 80, 81 urge the opposed siderails 83, 84 into firm engagement with each other. The contoured siderails 84 thus serve'to confine the expanding plastic composition 92 andprevent its expanding through the gaps 56 between the spaced-apartfirstand second flanges 45, 46 of the complementary facing sheets 35,36.

An alternative embodiment of the present mold apparatus Mis illustratedin FIGS. 4 and 5, wherein corresponding numerals are employed toidentify corresponding parts heretofore described.

FIG. 4 illustrates a lower mold platen 94 carrying the facing sheet 36.FIG. 5 illustrates an upper mold platen 95 containing complementaryfacing sheet 35 and engaged with the lower mold platen 94. The lower andupper mold platens 94, 95 have identical configurations.

Each of the mold platens 94, 95 comprises a mold plate 82 provided witha side rail 96 along the longitudinal side portions 76. The side rail 96includes afirst longitudinal face 86, a lengthwise depression 89, alengthwise projection 90 and a longitudinal extension or spacer element97. The spacer element 97 presents a plain surface 98 and a secondlongitudinal face 9 which is laterally offset from the firstlongitudinal face 86. The spacer element 97 has a width which is lessthan that of the side rail 96.

When assembled, the mold platens 94, 95 present confronting laterallyoffset, upper and lower generally U-shaped cavities 121, 122 eachdefined by the mold plate 82, the second longitudinal face 99 of thespacer element 97 and the first longitudinal face 88 of the side rail96. As shown in FIG. 5, each of the cavities 121, 122 receives one ofthe facing sheets 35, 36, respectively. Thus the mold apparatus Mpositions the complementary facing sheets 35 in fixed juxtaposed,laterally offset relation.

The mold platens 94, 95 receive the facing sheets 36, 35, respectively,with the central web 40 engaged with the mold plate 82 and with thesecond side wall 44 engaged with the face 86. When the mold platens 94,95 are assembled (FIG. 5), the plain surfaces 98 of the spacer elements97 engage the opposing mold plates 82 in the region of the side edge 75.The first side walls 43 of the facing sheets 35, 36 engage the faces 98of the spacer elements 97. The side rails 96 serve to align thecomplementary facing sheets 35, 36in juxtaposed, off set relation whenthe lower and upper molds 94, 95 are brought into assembled relation.

It will be noted that the upper and lower mold platens 80, 81 of themold apparatusM illustrated in FIGS. 1, 2, are identical. Likewide, theupper and lower mold platens 94, 95 of the mold apparatus M illustratedin FIGS. 4, 5 are identical. It will be appreciated that theconfiguration of the mold plate 82 corresponds to the configurationofthe central web of the facing sheet. Therefore, in that instance where,for example, the outer facing sheet has a profiled central web, the moldplaten carrying the facing sheet will have a correspondingly profiledmold plate. In that instance the upper and lower mold platens differwith respect to the mold plates but are identical with respect to theside rail configuration.

During fabrication of the building panel, a quantity of actively foamingplastic composition 92 (FIG. .5) is distributed along the length ofone'of the facing sheets, in this instance the inner facing sheet 36.While the plastic composition 92 is foaming, the upper mold platen 95containing the complementary'facing sheet 35, is engaged withthelowermold platen 94, as shown in FIG. 5. The opposed first and second sidewalls 43, 44 of each of the facingsheets 35, 36 confine the expandingplastic composition'93in a direction parallel with the central "webs 40.Accordingly, only unidirectional restraining pressures, applied in thedirection of the arrows 93 to the upper and lower mold platens 95, 94,are required by the present mold apparatus M. It will be appreciatedthat the unidirectional restraining pressures applied against the upperand lower mold platens 95, 94 urge the side rail 96 into firm engagementwith the mold plates 82. The side rails 96 thus serve to confine theexpanding plastic composition 92 and prevent its expanding throughthe-gaps 56 (FIG. 5)

between the spaced-apart first and second flanges 45,

46 of the complementary facing sheets 35, 36.

A further alternative embodiment of the present mold apparatus .M isillustrated in FIGS. 6 to 12, wherein corresponding numerals areemployed to iden tify corresponding parts heretofore described.

FIGS. 6 and 7 illustrate upper and lower mold platens 100, 101 havingsubstantially identical profiles. The upper mold platen includes a malespacer element 102 secured to the side portion 75 of the mold plate 82and a female side rail 103 secured to the opposite side portion 76 ofthe mold plate 82. The lower mold portion 101 includes a male spacerelement 104 secured to the side portion 75 of the mold plate 82 and afemale side rail 105 secured to the opposite side portion 76 0f the moldplate 82.

The male spacer elements 102, 104 are similar and present a base 106terminating in a flange 107, and a leading edge 108. The male spacerelement 104 additionally presents a shoulder 109 and an inner surface orface 110. The male spacer elements 102, 104 may be formedfrom aluminumby conventional extrusion processes.

The female side rails 103, 105 are similar and comprise a body portion111, a clamp block 114 and a gasket 115. The body portion 111 presents abase 112 overlying the edgeportion 76 of the mold plate 82 andterminates in a flange 113. The gasket 115 is interposed between thebody portion 111 and the clamp block 1 14. A fastener 116 extendingthrough the clamp block 114 and the gasket 115 into threaded engagementwith the body portion 111,.clamps the gasket 115 in position. The gasket115 presents a gasket surface 1 17 positioned for engagement by segmentsof the facing sheets tobe enclosed by the mold platens: 100, 101, aswill be described. Each of the female side rails 103, 105additionallypresent lengthwise recesses 118 positioned to receive theleading edge 108 of the confronting male spacer element 104, 102,respectively, see FIG. 7.

The female side rails 103, 105 differ from each other in the followingrespects. The female side rail 103 presents a shoulder 119 essentiallycoplanar with the gasket surface 117 and positioned for engagement withthe shoulder 109 of the confronting male spacer element 104, see FIG. 7.The female side rail 105 of the lower platen 101, presents a lengthwisetongue 120 extending beyond the gasket surface 117 toward the mold plate82 of the upper mold platen 100.

n will be observed in FIG. 6 that the u er mold platen 100 presents agenerally U-shaped cavity 121 definedby the mold plate 82, the spacerelement 102 and the side rail 103.. Similarly, the lower mold platen 101presents a U-shaped cavity 122 defined by the mold plate 82, the spacerelement 104 and the female side rail 105. When theupper and lower moldplatens 100, 101 are assembled (FIG. 7),the upper and lower generallyU-shaped cavities 121, 122, thereof are disposedin confronting,laterally offset relation.

The upper and lower mold platens 1'00, 101 are particularly adapted toreceive and position complementary upper and lower facing sheets 123A,1238 in fixed juxtaposed, laterally offset relation. For a completedescription of the facing sheets 123 as well as other facing sheetswhich may be supported by the present mold apparatus, attention isdirected to the aforesaid copending application Ser. No. 86,425.However, for the purposes of the present invention, it is believedsufficient to state that each of the facing sheets 123 includes acentral web 124 having upstanding first and second side walls 125, 127along the opposite longitudinal edges thereof. The first side wall 125terminates in a,

' first free edge 126. The second side wall 127 tenninates in. a flange128 which extends laterally therefrom in a direction away from thecentral web 124. The flange 128 is essentially parallel with the centralweb 124. The first and second side walls 125, 127 are provided withcomplementary mating elements in the form of a convex rib 129 (firstside wall 125) and a complementary concave rib 130 (second side wall127).

As best shown in FIG. 6, the lower facing sheet 123B is introduced intothe U-shaped cavity 122 with the convex rib 129 engaging the innersurface 110 of the male spacer element 104 with the flange 128 overlyingthe clamp block 1 14 and a portion of the gasket surface 117.

The complementary upper bacing sheet 123A is inverted and introducedinto the lower mold cavity 101' such that the convex rib 129 thereofengages the lengthwise tongue 120 and with the free edge 126 thereofengaging the gasket surface 117. Plural preformed support members 131(only one visible) are positioned at spaced locations along the lengthof the central web 124 of the lower facing sheet 1233 to support theflange 128 of the upper facing sheet 123A. The support blocks 131 may beretained in position by a film of adhesive (not shown).

During the fabrication of the present building panel, the upper moldplaten 100 (FIG. 8) may be tilted about the leading edge 108 of the malespacer element 102 to spread the female side rail 103 and the malespacer element 104 and thereby provide an opening 132 therebetween. Aquantity of actively foaming plastic composition 92 introduced throughthe opening 132, is distributed along the length of the lower facingsheet 1233. While the plastic composition is foaming, the upper moldplaten 100 is returned to the assembled relation illustrated in FIG. 7.It should be readily apparent by inspection of FIG. 7 that theinterengagement of the leading edges 108 with the lengthwise recesses118 lock the upper and lower mold platens 100, 101 together therebypreventing lateral displacement of the mold platen 100 relative to themold platen 101. Each of the gaskets 115 seals the gap between the freeedge 126 and the flange 128 of the complementary facing sheets 123,thereby confining the expanding plastic composition 92. Accordingly,only unidirectional restraining pressures, applied in the direction ofthe arrows 93 (FIG.'7) to the upper and lower mold platens 100, 101 arerequired by the present mold apparatus M. The unidirectional restrainingpressures urge each of the male spacer elements 102, 104 into firmengage ment with the confronting female side rail 105, 103,respectively.

In accordance with the present invention, at least one and preferablyboth of the mold platens 100, 101 have the generally rhomboidalconfiguration illustrated in FIGS. 9 and 10. For the purpose of thepresent invention, FIGS. 9 and illustrate the exterior face and theinterior face, respectively, of the upper mold platen 100. It is to beunderstood that the following description applies equally to the lowermold platen 101.

It will be observed in FIG. 9 that the male spacer element 102 presentsopposite ends 133, 134 extending beyond the corresponding ends of themold plate 82. Similarly, the female side rail 103 presents oppositeends 135, 136 extending beyond the corresponding ends of the mold plate82.

It will be observed in FIGS. 9 and 10- that the mold plate .82 presentsa plate portion 137 extending between the male spacer element 102-andthe female side rail 103. The plate portion 137 has a rhomboidalconfiguration including parallel side portions 75, 76 and parallelopposite ends 138, 139 extending diagonally between the parallel sideportions 75, 76.

It is a convenient concept when describing the mold platen 100 to statethat the male spacer element 102 (first mold plate side portion 75) islongitudinally offset relative to the female side rail 103 (second moldplate side portion 76).

Referring to FIG. 11, the upper mold platens 100 and the lower moldplatens 101 are adapted to be assembled in separate sets wherein themold platens are aligned in end-to-end abutted relation. For example, itwill be observed in FIG. 11 that at the joint between adjacent uppermold platens 100A, 100B, the projecting ends 134A, 136A of the moldplaten 100A abut the corresponding projecting ends 133B, 135B of theadjacent mold platen 100B. The overall arrangement is such that anoblique gap 140 is provided between the spaced-apart oblique ends 1398,139A. It has been discovered that the provision of the oblique gap 140precludes the formation of mold marks in the facing sheet contained inthe mold platens100A, 100B during the application of the unidirectionalrestraining pressures 93 (FIG. 7).

Referring still to FIG. 11, it will be appreciated that I a similaroblique gap 141 is provided at the joint betweenadjacent lower moldplatens 101C, 101D and 101D, 101E. The gaps 141 prevent the formation ofthe mold marks in the facing sheet contained in the lower mold platens101.

The upper and lower mold platens 100,. 101 may be assembled such thatthe oblique gaps and 141 intersect as shown in FIG. 11. Alternatively,the upper and lower mold platens 100, 101 may be assembled such that theoblique gaps 140 and 141 are spacedapart as shown in FIG. 12. It will beobserved that in either arrangement, the opposite ends 138, 139 of theset of lower mold platens 101 are parallel to each other but are notparallelvto the opposite ends 138, 139 of the set of upper mold platens.v It will also be appreciated that where the opposite ends 138, 139 ofthe mold platens 100, 101 are illustrated as straight ends, the oppositeends 138, 139

could,.for special purposes be made arcuate.

We claim: 1. Mold apparatus forpositioning complementary facing sheetsin fixed, juxtaposed, laterally offset rela-,

tion, said mold apparatus comprising a set of end abutted lower moldplatens and a set of end abutted upper mold platens, each of said moldplatens including: 1

a mold plate having opposite'ends and first and second opposite sideportions; va side rail secured to the first side portion of said moldplate and presentingan upper surface remote from said mold plate; and aspacer element secured to the second side portion of said mold plate;

said set of upper mold platens being assembled in tap posed relationwith said set of lower mold platens, with the spacer elements of eachsaid set engaging the side rails of the other said set;

said set of lower mold platens and said set of upper mold platens whenassembled, presenting confronting, laterally offset, upper and lowergenerally U- shaped cavities having opposite ends open to theatmosphere, each of said cavities being defined by the mold plates, thespacer elements and the side rails of one said set, and each beingadapted to receive one of said complementary facing sheets.

2. The mold apparatus defined in claim l wherein the mold platens of onesaid set present a lengthwise recess which is engaged by the confrontingspacer element of the mold platens of the other said set thereby lockingthe mold platens against movement laterally of each other.

3. The mold apparatus defined in claim 2 wherein said lengthwise recessis presented by the lower mold platens, exteriorly of the lower U-shapedcavity.

4. The mold apparatus defined in claim ll including a lengthwise tongueextending from the side rail of the lower mold platens above said uppersurface toward the mold plate of the upper mold platens.

5. The mold apparatus defined in claim l wherein each said side railcomprises:

a body portion secured to said first side portion of the mold plate; and

a resilient gasket secured to said body portion within the U-shapedcavity; 7

said upper surface of each said rail being provided,

at least in part, by said gasket.

6. The mold apparatus defined in claim ll wherein the spacer element ofsaid lower mold platens includes a shoulder spaced-apart from thecontiguous mold plate and disposed within the U-shaped cavity, saidshoulder being engaged by the side rail of said upper mold platens. 7.The mold apparatus defined in claim ll wherein said first and secondside portions of the mold plates of one said set are longitudinallyoffset relative to each other; and the opposite ends of the mold platesof said one set being obliquely presented with respect to said sideportions.

8. The mold apparatus defined in claim ll wherein the mold plates of onesaid set have a rhomboidal configuration.

9. The mold apparatus defined in claim h wherein the side rail and thespacer element of each mold platen of said one said set include endsextending beyond the corresponding ends of the mold plate and engagingthe side rail and the spacer element, respectively, of the adjacent moldplatens,

whereby the confronting ends of adjacent mold plat-' ens arespaced-apart and-present a gap therebetween.

10. The mold apparatus defined in claim l' wherein said first and secondside portions of the mold plates of each said set are longitudinallyoffset relative to each other; and wherein the opposite ends of the moldplates are obliquely presented; with respect to said side portions;

whereby an end portion of each mold platen of one said set is presentedin overlapping confronting re-.

lation with an end portion of an opposed mold platen of the other saidset.

11. The mold apparatus defined in claim l wherein the mold plates ofeach said set have a rhomboidal configuration.

12. The mold apparatus defined in claim llll wherein the side rail andthe spacer element of each mold platen of each said set include ll llends extending beyond the corresponding ends of the mold plate andengaging the side rail and the spacer element, respectively, of theadjacent mold platen, whereby the confronting ends of adjacent moldplates of each said set are spaced-apart and present a gap therebetween.

lid. The mold apparatus of claim posite ends of said set of lower moldto each other but are not parallel to said opposite ends of said set ofupper mold platens.

114. The mold apparatus of claim ll including means presented by themold platens of at least one said set for maintaining the confrontingends of ajdacent mold plates spaced-apart with a gap therebetween.

l5. Mold apparatus for fixedly positioning complementary facing sheetsin juxtaposed, laterally offset relation, comprising mold platens, eachincluding:

a mold plate having a first side portion and a second side portion; aside rail secured to the said mold plate along said first side portionand presenting an upper surface remote from said mold plate, said siderail having a first longitudinal face extending between said uppersurface and said mold plate, and positioned intermediate of the firstand second side portions of said mold plate; and

a spacer element carried at one of said side portions of said mold plateand presenting a second longitudinal face;

said mold platens adapted to be assembled in opposed pairs (a) with theuppersurface of each said side rail confronting the second side portionof the opposing mold plate and (b) with a said spacer positioned betweenthe upper surface of each said side rail and the second side portion ofthe opposing mold plate and (c) with the second longitudinal face ofeach said spacer element laterally offset from the first longitudinalface of theadjacent side rail and (d) with the upper surface of eachsaid side rail presented in confronting relation with the opposing rnoldplate;

said mold platens when assembled, presenting confronting, laterallyoffset, upper and lower generally U-shaped cavities, each defined by asaid mold plate, the second longitudinal face of a said spacer element,and the first longitudinal face of a said side rail, said cavities beingadapted to receive said complementary facing sheets and to retain thesame in juxtaposed laterally offset, physically separated relation.

id. The mold apparatus defined in claim l5 wherein each said spacerelement is secured to the said mold plate along the said second sideportion thereof.

17. The inold apparatus defined in claim 15 wherein each said spacerelement is connected to the said side rail above the said first sideportion of said mold plate. I lid. The mold apparatus defined in claimKEWhBIElll one of the mold platens presents a lenghtwise recess which isengaged by the confronting spacer element of the other mold platenthereby locking the mold platens against movement laterally of eachother.

W. The mold apparatus defined in claim 1h wherein said lengthwise recessis presented by the lower mold platen exteriorly of the lower U-shapedcavity.

2%. The mold apparatus defined in claim ltd wherein each said side railcomprises:

a body portion secured to said first side portion of the mold plate; and

a resilient gasket secured to said bdy portion within said lJ-shapedcavity;

said upper surface of each side rail being provided,

at least in part, by said gwltet.

v a t a a a ll wherein said opplatens are parallel

1. Mold apparatus for positioning complementary facing sheets in fixed,juxtaposed, laterally offset relation, said mold apparatus comprising aset of end abutted lower mold platens and a set of end abutted uppermold platens, each of said mold platens including: a mold plate havingopposite ends and first and second opposite side portions; a side railsecured to the first side portion of said mold plate and presenting anupper surface remote from said mold plate; and a spacer element securedto the second side portion of said mold plate; said set of upper moldplatens being assembled in opposed relation with said set of lower moldplatens, with the spacer elements of each said set engaging the siderails of the other said set; said set of lower mold platens and said setof upper mold platens when assembled, presenting confronting, laterallyoffset, upper and lower generally U-shaped cavities having opposite endSopen to the atmosphere, each of said cavities being defined by the moldplates, the spacer elements and the side rails of one said set, and eachbeing adapted to receive one of said complementary facing sheets.
 2. Themold apparatus defined in claim 1 wherein the mold platens of one saidset present a lengthwise recess which is engaged by the confrontingspacer element of the mold platens of the other said set thereby lockingthe mold platens against movement laterally of each other.
 3. The moldapparatus defined in claim 2 wherein said lengthwise recess is presentedby the lower mold platens, exteriorly of the lower U-shaped cavity. 4.The mold apparatus defined in claim 1 including a lengthwise tongueextending from the side rail of the lower mold platens above said uppersurface toward the mold plate of the upper mold platens.
 5. The moldapparatus defined in claim 1 wherein each said side rail comprises: abody portion secured to said first side portion of the mold plate; and aresilient gasket secured to said body portion within the U-shapedcavity; said upper surface of each said rail being provided, at least inpart, by said gasket.
 6. The mold apparatus defined in claim 1 whereinthe spacer element of said lower mold platens includes a shoulderspaced-apart from the contiguous mold plate and disposed within theU-shaped cavity, said shoulder being engaged by the side rail of saidupper mold platens.
 7. The mold apparatus defined in claim 1 whereinsaid first and second side portions of the mold plates of one said setare longitudinally offset relative to each other; and the opposite endsof the mold plates of said one set being obliquely presented withrespect to said side portions.
 8. The mold apparatus defined in claim 1wherein the mold plates of one said set have a rhomboidal configuration.9. The mold apparatus defined in claim 8 wherein the side rail and thespacer element of each mold platen of said one said set include endsextending beyond the corresponding ends of the mold plate and engagingthe side rail and the spacer element, respectively, of the adjacent moldplatens, whereby the confronting ends of adjacent mold platens arespaced-apart and present a gap therebetween.
 10. The mold apparatusdefined in claim 1 wherein said first and second side portions of themold plates of each said set are longitudinally offset relative to eachother; and wherein the opposite ends of the mold plates are obliquelypresented; with respect to said side portions; whereby an end portion ofeach mold platen of one said set is presented in overlapping confrontingrelation with an end portion of an opposed mold platen of the other saidset.
 11. The mold apparatus defined in claim 1 wherein the mold platesof each said set have a rhomboidal configuration.
 12. The mold apparatusdefined in claim 11 wherein the side rail and the spacer element of eachmold platen of each said set include ends extending beyond thecorresponding ends of the mold plate and engaging the side rail and thespacer element, respectively, of the adjacent mold platen, whereby theconfronting ends of adjacent mold plates of each said set arespaced-apart and present a gap therebetween.
 13. The mold apparatus ofclaim 1 wherein said opposite ends of said set of lower mold platens areparallel to each other but are not parallel to said opposite ends ofsaid set of upper mold platens.
 14. The mold apparatus of claim 1including means presented by the mold platens of at least one said setfor maintaining the confronting ends of ajdacent mold platesspaced-apart with a gap therebetween.
 15. Mold apparatus for fixedlypositioning complementary facing sheets in juxtaposed, laterally offsetrelation, comprising mold platens, each including: a mold plate having afirst side portion and a second side portion; a side rail secured to thesaid mold plate along said firSt side portion and presenting an uppersurface remote from said mold plate, said side rail having a firstlongitudinal face extending between said upper surface and said moldplate, and positioned intermediate of the first and second side portionsof said mold plate; and a spacer element carried at one of said sideportions of said mold plate and presenting a second longitudinal face;said mold platens adapted to be assembled in opposed pairs (a) with theupper surface of each said side rail confronting the second side portionof the opposing mold plate and (b) with a said spacer positioned betweenthe upper surface of each said side rail and the second side portion ofthe opposing mold plate and (c) with the second longitudinal face ofeach said spacer element laterally offset from the first longitudinalface of the adjacent side rail and (d) with the upper surface of eachsaid side rail presented in confronting relation with the opposing moldplate; said mold platens when assembled, presenting confronting,laterally offset, upper and lower generally U-shaped cavities, eachdefined by a said mold plate, the second longitudinal face of a saidspacer element, and the first longitudinal face of a said side rail,said cavities being adapted to receive said complementary facing sheetsand to retain the same in juxtaposed laterally offset, physicallyseparated relation.
 16. The mold apparatus defined in claim 15 whereineach said spacer element is secured to the said mold plate along thesaid second side portion thereof.
 17. The mold apparatus defined inclaim 15 wherein each said spacer element is connected to the said siderail above the said first side portion of said mold plate.
 18. The moldapparatus defined in claim 15 wherein one of the mold platens presents alenghtwise recess which is engaged by the confronting spacer element ofthe other mold platen thereby locking the mold platens against movementlaterally of each other.
 19. The mold apparatus defined in claim 18wherein said lengthwise recess is presented by the lower mold platenexteriorly of the lower U-shaped cavity.
 20. The mold apparatus definedin claim 15 wherein each said side rail comprises: a body portionsecured to said first side portion of the mold plate; and a resilientgasket secured to said bdy portion within said U-shaped cavity; saidupper surface of each side rail being provided, at least in part, bysaid gasket.